The Effects of Climate Change and Anthropogenic Activities on Groundwater in Irrigation District

Abstract

【Background and objective】 Groundwater is the most important water resource for agricultural production in many regions around the world and its spatiotemporal changes are affected by a multitude of natural and anthropogenic factors. Understanding their quantitative relationship is hence imperative not only to sustain agricultural production but also to safeguard the development of other sectors. Taking an irrigation district in central China as an example, this paper analyzed the fluctuation of its groundwater depth in response to climate change and anthropogenic activity. 【Method】 The analysis was based on groundwater and meteorological data measured from 1952-2013 from the People’s Victory Canal Irrigation District. Their changes and relationship were analyzed using the decadal volatility analysis, mutation test analysis, gray correlation analysis, sensitivity analysis, double cumulative curve method, and the relative contribution rate method. 【Result】 The groundwater depth in the district has been increasing at an average rate of 0.8 m/10a. The maximum coefficient of variation of the groundwater depth from 1952—1959 was 27.33%; the coefficients of variation of the precipitation, evaporation, average temperature and the amount of irrigation water all peaked in 1960s, though the variation of the evaporation and average temperature was not as strong as other factors. Abrupt changes in groundwater depth, precipitation, evaporation, average temperature and irrigation water amount occurred in 1984, 1970s, 1972, 1973 and 1993—1996, respectively. The influence of each factor on groundwater depth was ranked in the order of average temperature > precipitation > irrigation water amount > evaporation, while the sensitivity of groundwater depth to different factors was ranked in the order of average temperature > evaporation > precipitation > the amount of irrigation water. On average, the contributions of the different factors to groundwater depth change were ranked in the order of average temperature > evaporation > irrigation water amount > precipitation. The average temperature contributed most to the groundwater depth change accounting for 38.16%, and the least was precipitation contributing 17.40%. Irrigation water affected groundwater depth mostly from 2002 to 2013, contributing 47.05% of the change. 【Conclusion】 The factors affecting the groundwater depth in the district varied with time, with evaporation being dominant from 1952 to 1963, average temperature from 1964 to 2001, and irrigation from 2002 to 2013.

Keywords

• climate change
• human activities
• groundwater depth
• response characteristic
• relative contribution rate